Tempo and mode of mandibular shape and size evolution reveal mixed support for incumbency effects in two clades of island-endemic rodents (Muridae: Murinae)*

Dakota M. Rowsey, Lawrence R. Heaney, Sharon A. Jansa

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Existing radiations in a spatially limited system such as an oceanic island may limit the ecological opportunity experienced by later colonists, resulting in lower macroevolutionary rates for secondary radiations. Additionally, potential colonists may be competitively excluded by these incumbent (resident) species, unless they are biologically distinct (biotic filtering). The extant phenotypic diversity of secondary colonists may thus be impacted by lower rates of phenotypic evolution, exclusion from certain phenotypes, and transitions to new morphotypes to escape competition from incumbent lineages. We used geometric morphometric methods to test whether the rates and patterns of mandibular evolution of the Luzon “old endemic” rodent clades, Phloeomyini and Chrotomyini, are consistent with these predictions. Each clade occupied nearly completely separate shape space and partially separate size space. We detected limited support for decelerating and clade-specific evolutionary rates for both shape and size, with strong evidence for a shift in evolutionary mode within Chrotomyini. Our results suggest that decelerating phenotypic evolutionary rates are not a necessary result of incumbency interactions; rather, incumbency effects may be more likely to determine which clades can become established in the system. Nonincumbent clades that pass a biotic filter can potentially exhibit relatively unfettered evolution.

Original languageEnglish (US)
Pages (from-to)1411-1427
Number of pages17
JournalEvolution
Volume73
Issue number7
DOIs
StatePublished - Jul 2019

Bibliographical note

Funding Information:
We would like to thank the staff of the collections housing the specimens used in this study: N. Duncan, N. Simmons, R. Voss, and E. Westwig (AMNH); A. Ferguson, J. Phelps, and the late W. Stanley (FMNH); J. Chupasko (MCZ); and D. Lunde (USNM). F.K Barker, D. Fox, and K. McNulty provided comments on drafts of the manuscript. Travel expenses and equipment purchases were made possible by a Bell Museum of Natural History Dayton Wilkie Research Award and an American Society of Mammalogists Grant-in-Aid of Research awarded to DMR. DMR was also supported by the Wallace and Mary Dayton Fellowship and a Simons Fellowship awarded by the Bell Museum of Natural History. Field research that produced most of the specimens collected by LRH and deposited at FMNH has been supported by the Barbara Brown Fund for Mammal Research of the Field Museum and the Negaunee Foundation. Field research permits were provided by the Biodiversity Management Bureau of the Philippine Department of Environment and Natural Resources.

Funding Information:
DMR, LRH, and SAJ designed the research; DMR collected and analyzed the data; and DMR, LRH, and SAJ wrote the manuscript. We would like to thank the staff of the collections housing the specimens used in this study: N. Duncan, N. Simmons, R. Voss, and E. Westwig (AMNH); A. Ferguson, J. Phelps, and the late W. Stanley (FMNH); J.?Chupasko (MCZ); and D. Lunde (USNM). F.K Barker, D. Fox, and K. McNulty provided comments on drafts of the manuscript. Travel expenses and equipment purchases were made possible by a Bell Museum of Natural History Dayton Wilkie Research Award and an American Society of Mammalogists Grant-in-Aid of Research awarded to DMR. DMR was also supported by the Wallace and Mary Dayton Fellowship and a Simons Fellowship awarded by the Bell Museum of Natural History. Field research that produced most of the specimens collected by LRH and deposited at FMNH has been supported by the Barbara Brown Fund for Mammal Research of the Field Museum and the Negaunee Foundation. Field research permits were provided by the Biodiversity Management Bureau of the Philippine Department of Environment and Natural Resources. R code and digitized landmark coordinates can be found in the Dryad Digital Repository package. The doi for our data is https://doi.org/10.5061/dryad.gb7k5d1.

Publisher Copyright:
© 2019 The Author(s). Evolution © 2019 The Society for the Study of Evolution.

Keywords

  • Adaptive radiation
  • biotic filter
  • geometric morphometrics
  • interspecific competition
  • macroevolution
  • oceanic island

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